Earth Atmosphere Composition
Earth's atmosphere is a mixture of many gases. Its main part is nitrogen - 77 percent, the good old oxygen adds another 21 percent, the remaining 2 percent consists of a mixture of traces of gases - argon, carbon dioxide, helium, neon, krypton, xenon, nitrous oxide, carbon monoxide and others. The atmosphere also contains water vapor in various concentrations. Our favorite gas is oxygen, because we live thanks to this gas.
Premature infants whose lungs are underdeveloped are sometimes placed in oxygen containers in which the baby breathes a mixture with a high oxygen content.
Instead of the usual 21 percent, the oxygen concentration in such a container reaches 30 to 40 percent. If the child has severe respiratory distress, he breathes pure oxygen to avoid damage to brain cells.
Interesting fact: a large excess of oxygen in the inhaled gas mixture is just as dangerous as its deficiency.
The danger of excess oxygen and oxidation
Excess oxygen is just as dangerous as its lack. A large amount of oxygen in the gas mixture and its high concentration in the blood can destroy the cells of the tissues of the eyes of the child and cause vision loss. This fact underlines the dual nature of oxygen. To live, we must inhale oxygen, but oxygen itself is poison for living organisms. When air oxygen interacts with other elements, such as hydrogen and carbon, a reaction called oxidation occurs. Oxidation destroys the organic molecules that make up the core of life.At ordinary temperature, oxygen slowly reacts with other elements, and the heat generated is so insignificant that we do not feel it.
Temperature and oxidation
However, oxidation reactions rapidly accelerate with increasing temperature. Strike a match on the boxes. The friction between the match head and the abrasive strip on the box heats the match head. The oxidation reaction in this case proceeds quickly, and the match rapidly flames up. You see the light and feel the heat released during the oxidation reaction. In our organisms, oxidation is less dramatic. Red blood cells absorb oxygen from the air in the lungs and carry it throughout the body. Oxygen in living cells under strictly controlled conditions is much slower and not as hot as in the case of a burnt match, it oxidizes the food we eat. With this oxidation, food breaks down, as a result, energy is released, and water and carbon dioxide are formed. Carbon dioxide with blood is carried into the lungs and from them escapes into the atmosphere with exhaled air.
Interesting fact: pages of books turn yellow because they oxidize, that is, they slowly burn out.
Breathing enough oxygen is an absolute vital necessity. You can extinguish the fire with a thick blanket, blocking the access of oxygen to the fire. We may suffocate if for some reason we do not inhale oxygen for more than five minutes. The ideal oxygen level in the inhaled gas mixture is 21 percent, that is, the one we have in the atmosphere.But even then, oxygen often reveals its ferocious disposition. For example, dry grass can erupt from a single spark. The balance of oxygen and other gases is maintained in nature by the life cycles of plants and animals. Animals breathe carbon dioxide when breathing, and plants absorb it and in return emit oxygen.
Oxygen level
However, there is no guarantee that oxygen levels will remain the same for centuries as they are now. The amount of carbon dioxide released into the atmosphere is increasing. Its source is fossil liquid fuel, for example gasoline, fuel oil, during the combustion of which carbon dioxide is formed. At the same time, forests, the green lungs of the Earth, are being destroyed at an ever-increasing rate. In one minute, several hectares of forest are cut down. This combination predetermines a decrease in the oxygen content in the atmosphere, and scientists puzzle over how to reduce the damage done to it.
